1. Field of the Invention
The invention relates to a semiconductor device and method of fabricating the same, and more particularly, to a semiconductor device containing a light-emitting device and method of fabricating the same.
2. Description of the Prior Art
Because the advantages of long life span, light, low power consumption, and no mercury added, semiconductor light-emitting device, such as light-emitting diode (LED), has became a ideal lighting source and being developed. LED can be applied in several fields, include such as information, communication, consumer electronics, vehicles, traffic light, billboard and illumination market. The most popular fields includes the communication industry, such as the back light of cellular phones and the light of keys; the vehicle industry, such as the signal lights of cars and the dashboards of cars; and other illumination industries.
In the past, some methods of fabricating the semiconductor light-emitting device, such as the method disclosed in TW Pat. No. 68620, TW Pat. No. 96804, and TW Pat. No. 111466, are to use compound semiconductor, e.g., GaAs, InP, and Al2O3, to prepare the substrate. After the substrate prepared, to form a n-type or a p-type semiconductor on the substrate by epitaxy technology. However, because the compound semiconductor substrate is capable of absorbing the photon emitted from the light-emitting device, the light emitting efficiency is largely reduced. Moreover, because of the low thermal expansion coefficient of the compound semiconductor substrate, the semiconductor light-emitting device can not be operated under high current, and result in lower output power thereof. Furthermore, life of the semiconductor light-emitting device will easily be reduced because of the accumulation of heat generated by itself.
To overcome the disadvantages described above, many prior arts were disclosed in such as TW Pat. No. 573373, TW Pat. No. 565957, and TW Pat. No. 550834. These prior arts disclosed the method of adding metal material to the substrate of the semiconductor light-emitting device, so as to conduct the heat generated by the semiconductor light-emitting device. Therefore, the metal substrate allowed the semiconductor light-emitting device to be operated in a higher current and output power.
However, the difference of thermal expansion coefficient between conventional metal material, such as Ga, Cu, and Al, for the substrate and the epitaxy material is very large. Therefore, during the processes of fabricating the semiconductor light-emitting device, great stress will be generated between the substrate and the epitaxy, so as to destroy the epitaxy structure.